Shaft packing



F. LAvyAczEc 1,770,496

SHAFT PACKING 16 J U \\&\\\ 1 July 15, 1930.

Filed Aug. 24, 1921 Patented July 15, 1930 NITED STATES PATENT OFFICEFRANZ LAWACZECK, OF POGKING, UPPER-BAVARIA, GERMANY, ASSIGNOR TO WORTH-INGTON PUMP AND MACHINERY CORPORATION, OF NEW YORK, N. Y., A CORPO-SHAFT PACKING Application filed August 24, 1921, Serial No. 494,894, andin Germany August 25, 1916.

My invention relates to the packing of shafts and the like and moreparticularly to the packing by means of a liquid.

It has already been proposed to employ a liquid for effecting a perfectpacking of a shaft which passes through the casing of a machine orengine, but these devices are imperfect as they make use of a currentwhich is intended to circulate but in fact comes in contact with theliquid to be retained and therefore continuously carries away part ofthat liquid.

According to my invention, a perfect packing of a shaft is effected bymeans of a vis- 5 cous'liquid by arranging on the packing surface of apair of viscosity pumps having helical grooves and working in oppositedirections. In other words, I provide on the shaft or other part formingthe packing surface two comparatively very fine, helical grooves whichare very shallow in relation to their width'and extend in oppositedirections.

The depth of the 'said helical grooves, which may differ according tothe character of the viscous liquid, is seldom more than one to twohundredths of an inch. The dimensions specified probably cover most ofthe viscous liquids that will be employed, but may vary in accordancewith the viscosity of the liquid. There is a fundamental difference inresult and operation with grooves of these very shallow dimensions ofdepth over .the ordinary screw or helical grooves in that they makepossible successful functioning with a liquid of high viscosity,the.:fiow is substantially laminar without eddies being created, and thepressures developed are far greater. The pressure produced is a functionamongst other things," of the depth and length. and the pitch'of thegrooves, the width of the gap between the stationary and the rotatingpart and the number of revolutions or the circumferential velocity,respectively.

By providing two such pumps having viscosity grooves and operating inopposite directions, a stationary column of liquid under high pressureis formed where the two pumps adjoin or, generally speaking, in a spacein termediate the two pumps. This liquid column forms the packing forthe shaft. No separate chamber need be provided for the packing liquidand in many cases the narrow clearance between the revolving and thestationary part of the viscosity pump, a sleeve or the body of thebearing, in case that the viscosity pump is formed as a bearing, willsufiice.

Preferably the viscosity pump, which is nearest to the place to bepacked is provided with a longer or flatter groove or the like to renderthis groove capable of producing a higher pressure than the other one.This prevents the viscous liquid from entering the place to be packed.It is further advantageous to supply the viscous liquid not at one endof the viscosity groove pump, but at some points intermediate its endsand, if necessary, under pressure.

In the drawings affixed to this specification and forming part thereof asectional view of an arrangement embodying my invention is illustrateddiagrammatically by way of example.

Referring to the drawings, 1 is the shaft traversing two chambers 2 and3, the pressure in the chamber 2 in the example specified being assumedto be higher than the pressure in chamber 3. A liquid or high pressuresteam, any leakage of which along shaft 1 must be absolutely prevented,is supposed to fill chamber 2.

To this end, I provide on the shaft a plurality of viscosity groovepumps &, 5 and 6, the pumps 4 and 5 operating in opposite directions andbeing so designed that pump 4 is capable of producing a higher pressurethan pump 5. The viscous liquid is supplied to pump 5 through a bore 7.

Some part of the casing, such as a sleeve 8,

which is easily replaceable, tightly surrounds the shaft, in order toavoid an alteration of the width of the gap which might occur when theshaft 11 sinks owing to its bearings, wearing out. and which wouldinfluence its operat-ion very considerably, the sleeve 8 is preferablyadapted to be displacedin relatiOn to the casing and supported on shaft1 as illustrated. To this end, I may provide a diaphragm 9 or the likebetween sleeve 8 and the casing proper. Under certain conditions it maybe desirable toimake the endface of the sleeve 8 abut against a ring 11on shaft 1.

The outer helical pump 6 may be a continuation of pump 5 so that theliquid is supplied at 7 in a full turn of the helical groove. Thehelical groove 6 is provided more particularly in order to prevent theviscous liquid from leaking if supplied to the shaft under pressure, andto keep it moving toward the pump 5;

As the shaft starts rotating, the viscosity pump 5 forces the viscousliquid toward the chamber 2 as indicated by the arrow. The liquid willthen enter the first grooves of the opposite pump 4. This pump, however,being capable, when completely filled, owing to its longer or shallowergrooves, to produce higher pressure than pump 5, this pressurecounteracting the pressure produced by pump 5, its grooves are notfilled on their entire length and in the course of operation, a state ofequilibrium is reached in which the two pumps 4 and 5, where theyadjoin, maintain a viscous packing liquid under high pressure,

without this liquid being displaced considerably in one or the otherdirection. The stationary liquid in these parts of the packing surfaceswhich form part of both pumps, acts in the manner of a plug in relationto the difference of pressure between chambers 2 and 3 and absolutelyprevents any leakage of liquid or the like from chamber 2.

Preferably the viscous li uid supplied to the helical groove through ore7 p is grease contained in a grease cup 12 or some other suitable devicewhich exerts apermanent.

pressure on the packing liquid and the grease.

Instead of extending the thread of pump 4 down to the end of the casingsurrounding the helical groove, for instance the sleeve 8, I preferemploying a groove which ends at some distance from the end of theshaft, so that a smooth surface not provided with threads, extends inthe sleeve I wish it to be understood that I do not desire to be limitedto the exact details of construction shown and described, for obviousmodifications will occur to a person skilled in the art. For instance itis not necessary that all the viscosity groove pumps should have thesame diameter, as-illustrated.

I claim:

1. A device for placing viscous substances under pressure comprising incombination, members in contact with one another, one being adapted torevolve relatively to the other, a spiral groove in the contact surfaceof one of said members, means for feeding a viscous substance into thesuction end of said groove and another spiral groove in the contactsurface of one of said members arranged to feed towards the pressure endof said first groove.

2. Ina device for packing rotary shafts,

the combination with a shaft and a stationary part surrounding theshaft, of a viscosity thread pump, a second viscosity thread pump actingin the opposite direction thereto, the space between said pumps beingclosed to discharge, flat grooves between the threads of said pumps,said grooves being very shallow as compared with their width andsufficiently shallow to cause substantial laminar flow without eddies,and means for supplying said first mentioned pump with a viscous body ata point intermediate the ends of said pump.

3. In a device for packing rotary shafts, the combination with a shaftand a stationary part surrounding the shaft, of a viscosity thread pump,a second viscosity thread pump acting'in the opposite direction thereto,the

space between said pumps being closed to discharge and the groovesbetween the threads of said pumps being very shallow as compared withtheir width and sufliciently shallow to cause substantial laminar flowwithout eddies, and means for supplying only one of said pumps with aviscous body under pressure.

4. In a device for packing rotary shafts, the combination with a shaftand a stationary part surrounding the shaft, of a viscosity thread pump,a higher pressure viscosity thread pump acting in the opposite directionthereto, the s ace between said pumps being closed to discEarge, andmeans for supplying a viscous body under pressure solely to the firstmentioned pump.

5. In a device for packing rotary shafts, the combination with a shaftand a stationary part surrounding .the shaft, of a viscosity threadpump, a higher pressure viscosity thread pump acting in the oppositedirection thereto, the space between said pumps being closed todischarge, and means for so plying said, first mentioned pump with aviscous body at a point intermediate the ends of said first mentioned umIn testimony WhereOf l a x my signature. FRANZ LAWAGZECK.

